<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>属性选择器</title>
    <script src="../js/jquery-3.3.1.min.js"></script>
</head>
<body>
    <input type="text" id="txt">
    <input type="password">
    <input type="password">
    <input type="button" value="提交">
</body>
<script>
    //1.属性名选择器   $("元素[属性名]") 元素+[属性名][属性名]。。。：该元素标签下的所有属性
    let ins=$("input[type][id]");
    alert(ins.length)
    //2.属性值选择器   $("元素[属性名=属性值]")
    let pro=$("input[type=password]");
    alert(pro.length);
</script>
</html>